Integrated head package in place at Sanmen 1

14 March 2016

The integrated head package has been installed on top of the reactor pressure vessel of unit 1 of the Sanmen nuclear power plant in China's Zhejiang province. Sanmen 1 is expected to be the first Westinghouse AP1000 to begin operating.

The integrated head package combines several separate components in one assembly and aims to allow the rapid removal of the reactor vessel head during a refueling outage. It includes a lifting rig, seismic restraints for control rod drive mechanisms, support for reactor head vent piping, power cables, cables and a conduit for in-core instrumentation, cable supports and the cooling shroud assembly. Mounted directly on the reactor vessel head, the system helps to minimize the time, manpower and radiation exposure associated with head removal and replacement during refueling.

Installation of Sanmen 1's integrated head package (Image: SNPTC)

The integrated head package for Sanmen 1 was installed on the reactor vessel on 11 March, plant constructor State Nuclear Power Technology Corporation (SNPTC) announced the following day. The lifting process to install the 215-tonne component lasted about two hours, the company said.

The device was produced in China by SNPTC subsidiary Shandong Nuclear Power Equipment Manufacturing and assembled at the Sanmen construction site.

In September 2007, Westinghouse and its partners the Shaw Group received authorization to construct four AP1000 units in China: two at Sanmen and two more at Haiyang in Shandong province.

Sanmen unit 1 is expected to be the first AP1000 to begin operating, in September, while Haiyang 1 is expected to start up by the end of the year. Containment tests have already been successfully conducted at both units. All four Chinese AP1000s are scheduled to be in operation by the end of 2017.

Four AP1000 reactors are being built in the USA - two each at Vogtle and Summer - while three AP1000s are also proposed for the Moorside site in the UK.